Arctic Sea Ice Continues Decline, Hits 2Nd-Lowest Level

Arctic sea ice continues decline, hits 2nd- lowest level 5 October 2011, By Patrick Lynch

seas as well as other factors that are making the ice more vulnerable."

Joey Comiso, senior scientist at NASA's Goddard Space Flight Center in Greenbelt, Md., said the continued low minimum sea ice levels fits into the large-scale decline pattern that scientists have watched unfold over the past three decades.

"The sea ice is not only declining, the pace of the decline is becoming more drastic," Comiso said. "The older, thicker ice is declining faster than the rest, making for a more vulnerable perennial ice NASA satellite data reveals how this year's minimum cover." sea ice extent, reached on Sept. 9 as depicted here, declined to a level far smaller than the 30-year average While the sea ice extent did not dip below the 2007 (in yellow) and opened up Northwest Passage shipping record, the sea ice area as measured by the lanes (in red). Credit: NASA Goddard's Scientific microwave radiometer on NASA's Aqua satellite did Visualization Studio drop slightly lower than 2007 levels for about 10 days in early September, Comiso said. Sea ice "area" differs from extent in that it equals the actual surface area covered by ice, while extent includes (PhysOrg.com) -- Last month the extent of sea ice any area where ice covers at least 15 percent of covering the Arctic Ocean declined to the second- the ocean. lowest extent on record. Satellite data from NASA and the NASA-supported National Snow and Ice Arctic sea ice extent on Sept. 9, the lowest point Data Center (NSIDC) at the University of Colorado this year, was 4.33 million square kilometers (1.67 in Boulder showed that the summertime sea ice million square miles). Averaged over the month of cover narrowly avoided a new record low. September, ice extent was 4.61 million square kilometers (1.78 million square miles). This places The Arctic ice cap grows each winter as the sun 2011 as the second lowest ice extent both for the sets for several months and shrinks each summer daily minimum extent and the monthly average. Ice as the sun rises higher in the northern sky. Each extent was 2.43 million square kilometers (938,000 year the Arctic sea ice reaches its annual minimum square miles) below the 1979 to 2000 average. extent in September. It hit a record low in 2007. This summer's low ice extent continued the The near-record ice-melt followed higher-than- downward trend seen over the last 30 years, which average summer temperatures, but without the scientists attribute largely to warming temperatures unusual weather conditions that contributed to the caused by climate change. Data show that Arctic extreme melt of 2007. "Atmospheric and oceanic sea ice has been declining both in extent and conditions were not as conducive to ice loss this thickness. Since 1979, September Arctic sea ice year, but the melt still neared 2007 levels," said extent has declined by 12 percent per decade. NSIDC scientist Walt Meier. "This probably reflects loss of multiyear ice in the Beaufort and Chukchi "The oldest and thickest ice in the Arctic continues

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to decline, especially in the Beaufort Sea and the Canada Basin," NSIDC scientist Julienne Stroeve said. "This appears to be an important driver for the low sea ice conditions over the past few summers."

Climate models have suggested that the Arctic could lose almost all of its summer ice cover by 2100, but in recent years, ice extent has declined faster than the models predicted.

NASA monitors and studies changing sea ice conditions in both the Arctic and Antarctic with a variety of spaceborne and airborne research capabilities. This month NASA resumes Operation IceBridge, a multi-year series of flights over sea ice and ice sheets at both poles. This fall's campaign will be based out of Punta Arenas, Chile, and make flights over Antarctica. NASA also continues work toward launching ICESat-2 in 2016, which will continue its predecessor's crucial laser altimetry observations of ice cover from space.

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